Roofing removal process and machine

ABSTRACT

Disclosed herein is a method for stripping roofs and a roof stripping machine which includes a double-edged blade reciprocal along the path of advance of the roof stripper and means for independently advancing the stripper forwardly and rearwardly at speeds independent of blade reciprocation and of the rate of blade reciprocation and simultaneously with such reciprocation.

[451 Oct. 3, 1972 United States Patent Rothi et al.

[541 ROOFING REMOVAL PROCESS AND MACHINE [72] Inventors: Raymond C. Rothi, W. St. Paul,

172/20 .299/37 Ditter.......................... 11/1970 Probst.......................

.299/37 6/1935 Overell........................299/37 3/1944 Phillips........................

2/1959 Singleterry et 9/1959 172/19 ..299/37 Minn.; William D. Wright, Detroit, Mich.

[73] Assignee: Outboard Marine Corporation,

Waukegan, [11.

Primary Examiner-Emest R. Purser Attorney-Spencer B. Michael Robert K. Gerling,

[22] Filed: March 2, 1970 Robert E. Clemency, John N. Michael, Gerrit D. Foster, Bayard H. Michael, Paul R. Puerne A. Gemignani and Andrew D. Riteris 211 Appl. No.: 15,645

r, Joseph ABSTRACT Disclosed herein is a method for stripping roofs and a roof stripping machine which includes a double-edged [52] US. Cl........................299/l0, 15/93 R, 30/170, [57] blade reciprocal along the path of advance of the roof stripper and means for independently advancing the stripper forwardly and rearwardly at speeds indepenblade reciprocation and of the rate of blade d t n e 0 man 3 7 ew MUN 01 m s i m E mm m T u, A m G P S W 6 E i m T u e A u r T "m .m S mh e D mm R E W n N l m U d Ld .mF M U U a w m C m h c m U s w h i m g y o m m a m n m m .m s d n G a n M .m m r .W m O mfi 7 7 Bun 9 9 3W3 "9 mlm m. H mow KCC 0 6 556 999 111 0085 sum 1 BF 3 ATTO PATENTEDUBU I972 SHEET 3 [IF 3 If M 63m 0 m ec w i 0 m YL 2W EWWM, w

AT TO RNEYS ROOFING REMOVAL PROCESS AND MACHINE BACKGROUND OF THE INVENTION In the past, stripping of roofing material from roofs to reduce the weight of the roof in preparation for the application of new roofing material has involved many long and tedious hours of manual labor. For many years prior to the invention disclosed herein, there was no known machine commercially available for removing roofing material from a roof.

SUMMARY OF THE INVENTION vide an opening or hole having sufficient depth and area to locate the blade therein at the desired cutting depth.

Accordingly, the invention provides, in part, a method of stripping roof material comprising the steps of cutting an opening in a roof, locating in the opening material and simultaneously reciprocating and translating the blade in the horizontal direction.

Also in accordance with the invention, there is provided a machine for stripping roofs which includes a wheel arrangement for supporting and horizontally advancing the machine, a cutting blade which, in the preferred construction is double-edged, a structure for supporting the cutting blade and for horizontally reciprocating the blade at the same time the machine is horizontally advancing, and independently operated power delivery control mechanisms interposed between an engine and each of the wheel arrangement and the blade reciprocating drive.

In this last regard, the power driven control wheels affords speed and direction control, including neutral, independently of the engine and without affecting the drive to the reciprocating blade. It is preferred that the power delivery control mechanism be a hydrostatic transmission unit with appropriate controls. Also included, in series with the hydrostatic unit is a clutch which affords disconnection of the drive wheels from the hydrostatic unit to afford free wheeling of the machine when the engine is not running.

The power delivery control mechanism interposed between the engine and the blade permits discontinuance of blade operation without affecting power delivery to the drive wheel, thereby affording powered transport of the machine without reciprocating operation of the blade.

Employment of a sharp edge at the rear of the blade, as well as at the front thereof, together with provision for traction or drive in reverse is particularly useful in connection with stripping of roofs having upstanding walls along the outer roof edges. In this regard, the ability to run in reverse and to cut in reverse is particularly helpful in removing the machine from against such walls.

In general, one of the principal objects of the invention is the provision of a superior method for stripping roofing material from a roof.

.a cutting blade situated below the top of the roof I Another principal object of the invention is the provision of a machine for stripping roofing material from a roof. 9

A still further object of the invention is the provision of a roof stripping machine having independently controlled traction and blade actuation.

A still further object of the invention is the provision of a roof stripping machine which has a throttle control for an engine whereby to control the power available to the reciprocating blade and which machine also employs an auxiliary control capable of regulating the speed of advance of the machineindependently of the throttle control. p

Still another object of the invention is the provision of a roof stripping machine having a novel caster wheel arrangement for supporting the machine.

Other objects and advantages will become known by reference to the following description and accompanying drawings in which:

DRAWINGS FIG. 1 is a perspective view of a roof remover embodying various of the features of the invention.

FIG. 2 is a fragmentary view partially broken away and in section of portions of the roof remover shown in FIG. 1.

FIG. 3 is a fragmentary view, partially in section, taken along line 3-3 of FIG. 2.

FIG.'4 is a fragmentary view of a control mounted on the roof remover shown in FIG. i1.

FIG. 5 is a sectional view taken along line 5-5 of FIG.-4.

FIG. 6 is a sectional view taken along line 66 of 'FIG. 4.

A mechanism between the engine and the drive wheel or FIG. 7 is a perspective view of the roof removing blade incorporated in the roof remover shown in FIG.

DETAILED DESCRIPTION Shown in the drawings is a machine or roof remover 11 for removing roofing material, which machine is in accordance with the invention. As shown in FIG. 1, the machine or roof remover 1 1 includes ,a frame 13 which also serves as a gear box. Extending from the frame 13 is a handle structure 17 whichsupports certain controls which will later be described. Mounted on a forwardly extending shelf or member 19 supported from the frame 13 is an internal combustion engine 21 which is controlled by a throttle control or lever 23 carried on the handle structure 17. Supporting the frame 13 on the ground are a pair of axially aligned traction wheels 27 (only one being shown), which wheels 27 are fixed to a cross shaft 29 (See FIG. 2) rotatably supported by the gear box or frame 13. Internally of the gear box 13, the cross shaft 29 is fixed to a sprocket 31 which is connected by a chain 33 to a sprocket 37 fixed on a second cross shaft 39 also rotatably supported in the gear box 13. Carried on the cross shaft 39 for rotative and axial movement relative thereto, is a gear 41 which meshes with another gear or pinion 43 fixed on still another cross shaft 47 rotatably supported in the gear box 13.

sectional view taken along line Means are provided for interrupting the deliver of power from the gear box 13 to the traction wheels 27 by means of a clutch 45 or disconnect switch (See FIG. 3) interposed between the gear 41 and the sprocket 37. More particularly, the gear 41 and the sprocket 37 on the cross shaft 39 respectively include hubs 49 and 51 which are located in facing relation to each other and which include interengageable lugs 53 and recesses 57. In order to engage and disengage the clutch 45, the hub 49 of the gear includes an annular groove 59 receiving an actuating fork 61 which extends from a block 63 slideably mounted on a cross rod 67.

Lateral shifting of the fork 61 on the rod 67 gage and disengage the clutch 45 is provided by a lever 69 which is located exteriorly of a portion of the top surface of the gearcase and which is connected to a shaft 71 extending downwardly into the gearcase. The shaft 71 carries an eccentric or'offset pin 73 whichis received in a fore and aft slot 77 on the block 63 from which the yoke or fork 61 extends. Thus, pivotal moveeach of the ends of the web, a vertically extending leg.

83. Means are provided for reciprocating the blade in the direction of vehicle travel and for raising and lowering of the blade 79 and for changing the angle of attack of the blade 79. More particularly, in the disclosed coni struction, such means includes, on each side of the machine, a side leg or member 87 which, at its lower end, is connected to the upper end of one of the blade legs 83 and which, at its upper 'end (See FIG. 1), is

bottom ends, are each pivotally connected at 112 at the tending about the axis of the cross shaft 93. Fixed to the cross shaft 93 to effect rocking movement thereof and of the arms 91' to raise and lower the pivots 89, and therefor the blade 79, is a handle which can be locked in. the desired position by a clamp 129 extending through the arcuate slot 123 and connected to the handle 127.

Reciprocating movement of the blade 79 is afforded, at each side of the machine 1 l, by pitmans or arms 131 which are connected, at their forward ends, to each other by a cross'shaft 133 and, through hearings, to the lower ends of the side legs 87.

At each side of the machine, the pitmans or arms 133 v bushing 141 which is rotatably received in a socket 143 at the other end of the pitmans or arms. In turn, the shaft 137 has fixed thereon, internally of the gearcase 13; one or more sprockets 147 around which there is trained one or more chains 149 which are also trained (See also FIG. 3) around one or more other sprockets 151 fixed on still another cross shaft 153 journaled in the gear box. This last mentioned cross shaft 153 extends exteriorly of the gear box 13 and has mounted on the projecting end 157 thereof a sheave or pulley 159 (See also FIG. 1) which, in turn, is connected by a flexible endless belt 161 to a pulley or sheave 163 mounted on the output shaft 167 of the engine 21. Accordingly,

as thus far described, operation of the engine 21 will cause reciprocation of the blade 79 and variation in em gine speed will cause similar variation in the rate of blade reciprocation.

The construction of the machine as. thus far described, is essentially that of a prior art cutter before modification in accordance with the invention.

In accordance with the invention, means are provided for controlling the rate and direction of movement of the frame 13 independently of reciprocation of the blade 79 and independently of the rate of blade reciprocation. In addition, means are provided for discontinuing reciprocation of the blade 79 notfwithstanding continued operation of the engine 21 and opposite sidesof the machine to separate support 5 plates 113 fixed at 114 in upstanding relation to the frame or gear box 13. r

The angular position of the l-l-shaped member 99 relative to the gear box 13 can be adjustably fixed to vary the angle of blade attack by a clamp (not shown) which includes a handle (not shown) and across a member 117 which extends through the lower legs 111 of the H-shaped supporting member 99and through arcuate slots 1 19 in each of the support plates 113. Thus, the H-shaped supporting member can be rocked about its pivotal connections 112 to the support plates 113 and fixed in any desired position by the clamp to obtain the desired angle of blade attack.

Adjustment of the height of the blade 79 or change in the depth of cut is accomplished by rocking the cross shaft 93 whereby to raise and lower the pivots 89 about which the legs 87 and blade 79 rock. In this regard, there is fixed to the l-I-shaped supporting member 99 a quadrant member 121 having an arcuate slot 123 ex-' without affecting the delivery of power from the engine 21 to the traction wheels 27. e 1

While various arrangements may be used, the means for controlling the rate and direction of travel of the roof remover independently of reciprocation of the blade or independently of the rate of blade reciprocation includes a hydrostatic transmission unit 171 which is mounted on an upright extension 173 of the frame or gear box 13- and which includes (See FIG. 1) an input shaft 177, an output shaft 179 (See FIG. 10), and a control arm or lever 181 (See FIGS. 2 and 3).

The hydrostatic transmission unit 171 is of conventional construction and is operable upon rotary input in one rotative direction through the input shaft 177 to effect variation in both the direction and rate'of output shaft rotationin accordance with the location of r the control arm 181. More particularly, when the control arm 181 is in centered position, the transmission unit 171 is in neutral and the output shaft 179 does not rotate regardless of the rotation of the input shaft 177. Movement of the control arm 181 in one direction from centered position effects rotation of the output shaft 179 in one direction and at an increasing rate as the distance from the centered position increases. Movement of the control arm 181 in the other direction from centered position effects rotation of the output shaft in the opposite direction at a rate which increases with increasing distance from the centered position. Make-up oil, as necessary, is supplied to the hydrostatic unit 171 through a conduit 187 (See FIG. 2) connected to a reservoir 189 located in the upper part of the gear box extension 173.

Rotary input to the hydrostatic transmission unit 171 is provided through a pulley 191 fixed to the input shaft 177 and operatively connected to an endless belt 193 which is also trained around a second pulley or sheave 197 which is connected to the engine output shaft 167 independently of the pulley or sheave 163 which delivers power to the reciprocating blade 79.

Fixed on the output shaft 179 of the hydrostatic unit 171 interiorly of the gear box extension 173 is a sprocket 199 which is connected through a chain 211 to a sprocket 213 fixed on the before-mentioned cross shaft 47 within the gear box 13, whereby to complete the power delivery train from the engine 21 to the traction wheels 27.

From the foregoing, it will be noted that the drive to the traction wheels 27 can be controlled, independently of the drive to the cutting blade 79, by both the clutch 45 and the hydrostatic transmission unit 171. It should also be noted that as a consequence of use of the hydrostatic transmission, the roof remover 11 can be operated either forwardly or rearwardly at variable speeds, or when in neutral, without travel, regardless of the power output of the engine 21. This arrangement is very desirable as it permits delivery of relative large amounts of power to the blade 79 while simultaneously affording close control of the rate of vehicle movement, whereby to assist effective heavy duty cutting.

As already noted, the roof remover 11 also includes means for controlling delivery of power to the cutting blade 79 independently of the delivery of power to the traction wheels 27. While various arrangements can be employed, in the disclosed construction, there is provided a combination brake and belt tensioning device 217 operable upon the belt 161 which delivers power solely to the cutting blade 79.

Structurally, the belt braking and tensioning device 217 is essentially the same as previously employed in prior sod cutters to control power delivery from the engine to both the traction wheels and the cutting blade. More particularly, in the disclosed construction, the belt braking and tensioning means 217 includes a fixed braking pin 219 which is located below the lower run of the belt 161 and an arm 221 which is pivotally mounted to the engine at 223 and which carries a first pin 227 engageable with the top surface of the upper run of the belt 161 and a second pin 229 engageable with the upper surface of the lower run of the belt 161 in opposing relation to the fixed pin 219. The arm 22] is biased into a braking position with the pins 219, 227 and 229 against the belt in such manner as to capture the belt 161 between the pins 219 and 229 and to somewhat disengage the belt 161 from the pulley 163 by atensioning spring 231 fixed at one end to the movable arm 221 and anchored at the other end to the engine 21.

Movement of the arm 221 in the counterclockwise direction about the pivot 223 as seen in FIG. 1 and away from its braking position just described is afforded by engagement with the arm 221 by a pin 233 which extends from an arm or lever 237 projecting from a cross shaft 239 pivotally mounted on the gear box 13. Also carried by the lever 237 is an idler wheel 241 engageable with the belt 161 to effect tightening thereof around the pulley 163 upon clockwise movement of the lever 237. Such movement of the lever 237 also engages the pin 233 with the arm 221 to move the arm 221 away from its braking position against the action of the spring 231. Such clockwise movement of the lever 237 is afforded by common movement with the cross shaft 239 which is connected through a bell crank lever 243 to a rod 245 which, in turn, is connected to an operating lever 247 having an over-center mounting on the handle structure 17. Such over-center mounting of the handle or lever 247 permits retention of the biased components of the device 217 in a non-braking position, notwithstanding action of the spring 231. When the operating lever 247 is in its forwardmost position, the arm 221 is urged to its braking position by the spring 231 and the idler wheel 241 is not in operative engagement with the belt 161'. When the operating lever 247 is rocked rearwardly in the clockwise direction, the arm 221 is retracted from its braking position by operation of the pin 233 against the arm 221 and the idler wheel 241 is swung into a position tightening the belt 161 around the pulley 163.

Also mounted on the handle structure 17' is a control 251 for the hydrostatic transmission unit 171. This control 251 comprises, as seen best in FIGS. 4, 5, and 6, a handle 253 which is connected to the control arm 181 of the hydrostatic transmission unit 171' by a rod 257 and which is pivotally mounted at 259 to a guide member 261 fixed to the handle structure 17. The handle 253 is movable through a slot 263 which is provided in the guide member 261 and which has laterally offset,but communicating,legs 267 and 269 in the sense that the leg 267 affords movement of the handle 253 from an upright neutral position. in the clockwise direction rearwardly to effect rearward drive and in the sense that the leg 269 is laterally offset from the rearwardly extending leg 267 and affords movement of the handle 253 from the upright neutral position in the counterclockwise direction to effect forward drive. Thus, shifting between forward and reverse" drive cannot be accomplished by shifting the handle 253 in a single plane as it is necessary to laterally shift the handle 253 on its pivot 259 to locate the handle 253 for travel from either of the laterially ofiset slot legs 267 and 269 to the other.

In accordance with the invention, in order to return the transmission unit from rearward drive to neutral in the absence of a retaining force, the handle 253 is biased toward the neutral position and against a shoulder 277 at the forward end of the slot leg 267 by a spring 273 located around the pivot 259. This arrangement has the very beneficial advantage of automatically returning the drive to neutral if the operator should, for any reason, fail to retain his handin operatingcontrol of the handle 253 when the machine 11 is in reverse drive. Thus, rearward movement of the machine toward a disabled operator is prevented.

In addition, means are provided for biasing the lever toward the right in FIG. 6, i.e., along the pivot 259 toward the slot leg 267. This arrangement serves to prevent unwanted control handle movement into the forward leg 269 when returning from a rearward drive setting to neutral and of engaging the handle lever with a serrated slot edge when the handle is in the forward slot leg 269 to retain the handle in any selected forward drive position.

More specifically, a spring 279 is located about the pivot 259 in position to laterally displace the handle 253 toward the slot 267 as compared to the slot 269. In addition, the slot 269 includes the just mentioned serrated edge 281 which cooperates with a pair of ribs 283 on the handle 253 to retain the handle in any selected forward drive setting.

Also in accordance with the invention, the frame or gear box 13 is supported (See FIGS. 1 and 2) at its rearward end so as to provide maneuverability and to afford temporary variation in depth of cut by a semipneumatic tire or caster wheel 287 carried for rotation about a horizontal axis 289 and for turning through 360 about a vertical axis 291 on the rearwardmost link 293 of a parallel linkage 297 having, on each side, upper and lower links 299 and 301 respectively, which are pivotally connected at their forward ends to the gear box 13 and, at their rearward ends, are pivotally connected to the rear link 293. The linkage 297 is retained to support the blade 79 in proper position for cutting action by a pair of springs 311 which as shown, are connected, at their lower ends, to the frame or gear box 13 below the pivotal connection of the lower links 301 and are connected, at their upper ends, to an ear 313 extending from the upper part of the rear link 293. The springs 311 urge the rear link 293 upwardly until a stop 310 formed thereon engages the upper surface of at least one of the links 299, thereby to support the rear of the machine and to prevent lowering of the machine by its own weight. In operation, the arrangement for spring support of the rear of the frame or gear box 13 can be overcome by the operator to tilt the machine 11 about the traction wheels 27 so as to change the depth of cut by temporarily varying the force applied to the handle structure 17 as maybe desired.

Also in accordance with the invention, the roof remover is adapted to cut in response to both forward and rearward movement. In this regard, both the transversely horizontal web 81 and the sides 83 of the cutting knife or blade 79, as shown best in FIGS. 7 through 9, are sharpened along both the forward and rearward edges to provide cutting edges indicated at A whereby to afford cutting capability when the device is traveling either rearwardly or forwardly. This is of particular significance when the machine cannot be advanced further, as when the machine is approaching a bordering wall around a roof and it is therefor desired to extricate the machine and in particular to cause the blade to be removed from under the previously cut strip of roofing material. More particularly, the rearward cutting capacity coupled with the rearward drive capability and the caster support of the frame at the rear, facilitates such rearward turning movement of the machine so as to transversely arcuately sever the previously cut strip and afford extrication of the blade.

Also in accordance with the invention, the web 81 of the blade 79 is located relative to the blade legs 81 so as to facilitate cutting into the roof at an angle to the horizontal and thereby to prevent the blade 79 from camming out of the roofing surface to the removed. In this regard, the angle between the front edge 82 of the side legs and the flat undersurface 84 of the web 81 is approximately 47, although some degree of variation can be employed. In addition, when in static condition, it is preferable that the bottom surface 84 of the web be at an angle of about 1 1 to the horizontal roof line.

It is believed that the best performance will occur when the angle between the flat bottom surface 84 of the web and the horizontal roof line is within a range of from about 4 to about 20.

Connected to the frame 13 is a lifting hook 327 affording hoisting of the roof remover 11 to the top of buildings.

In operation, in accordance with the method of the invention, the roof 321 (as shown in FIG. 2) is initially prepared by cutting therein an opening 323 sufficiently large and deep to permit receipt and initial reciprocation of the cutting blade 79 at the desired depth. Thereafter, with the blade 79 reciprocating, the machine 11 is advanced at the desired speed by operation of the hydrostatic transmission unit 171. As already noted, the engine throttle control 23 can be adjusted to apply whatever level of power is desired to the blade 79 for the cutting operation, while simultaneously permitting independent control of the rate of forward or rearward travel. As also already noted, the machine 11 can be rearwardly extricated at the end of a cut by operating the machine in reverse and simultaneously withdrawing and turning the machine through an arc of about to transversely sever the previously cut strip.

When desired, the blade drive can be stopped by operating the belt braking and tensioning device 217 and the machine 11 can be power driven as desired from place to place. If the engine should become inoperative for one reason or another, the machine 11 can be free-wheeled for manually powered travel by disengagement of the clutch 45. In addition, if the operator fails to maintain his hand in operating control of the lever 253 while the machine is moving rearwardly, the lever 253 will automatically return to its neutral position by action of the spring 273 and thereby prevent further rearward advance of the machine toward the operator. Thus, there is provided a machine which is particularly well adapted for effective removal of roofing material.

Various features of the invention are set forth in the following claims.

What is claimed is:

1. A method of stripping roofing material from a roof comprising the steps of reciprocating a blade having horizontal and vertical cutting edges relative to the roofing material, translating the blade into the roofing material while continuing said reciprocating of the blade so as to cut the roofing material both horizontally and vertically to form a strip of roofing maten'al severed frornthe roof, translating the blade in the opposite direction from the previous translation while maintaining said reciprocating of the blade, and simultaneously turning the blade across the previous path of the blade .9 so as to cut the roofing material with the rear of the blade.

2. A method of stripping roofing material from a roof comprising the steps of reciprocating a cutting blade having a web with a cutting edge and a supporting leg with a cutting edge relative to the roofing material, simultaneously translating the blade into the roofing material to cut the roofing material by the web and the leg of the blade, translating the blade in the opposite direction from the previous translation while maintaining said reciprocating of the blade, and simultaneously turning the blade across the previous path of the blade so as to cut the roofing material with the rear of the blade.

3. A roof remover comprising a frame, an engine mounted on said frame, a blade having sharpened forward and rearward edges and being mounted on said frame for horizontal reciprocating movement in response to operation of said engine at speeds in accordance with engine speed, a drive wheel mounted on said frame, and power delivery means on said frame for delivering power to said drive wheel from said engine independently of power delivery to said blade by said engine and for selectively driving said drive wheel in forward drive and in reverse drive.

4. A roof remover in accordance with claim 3 wherein said power delivery means includes a control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in a reverse drive condition, for returning said lever to neutral upon removal of a manually applied force acting in opposition to said lever returning means.

5. A roof remover in accordance with claim 3 wherein said power delivery means includes a control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in said forward drive condition, for releasably retaining said lever in a selection position.

6. A roof remover in accordance with claim 3 wherein said power delivery means includes a pivotally mounted control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in a reverse drive condition, to prevent pivotal movement of said lever in one plane from rearward drive condition to forward drive condition.

7. A roof remover in accordance with claim 3 wherein said power delivery means includes a guide member having therein a slot with communicating laterally offset legs, a lever pivotally mounted with respect to said guide member and extending through said slot, means biasing said lever in the direction toward the end of one leg adjacent said other leg, and means biasing said lever along its pivotal axis toward said one leg.

8. A roof remover in accordance with claim 3 including means for selectively driving said blade by said engine independently of the operation of said drive wheel by said engine.

9. A roof remover in accordance with claim 8 wherein said means for selectively driving said blade by said engine includes an endless belt and a device mounted on said frame and including components movable between a first position effecting braking of said belt and a second position in non-braking relation to said belt, said second position effecting tensioning of said belt to afford effective power delivery thereby.

10. A roof remover in accordance with claim 9 wherein at least some of the said components are biased to said first or belt braking position and including a control handle having an over-center mounting affording movement between a belt tensioningposition and a belt braking position, whereby to effectively overcome said biasing when said handle is in said belttensioning position.

11. A roof remover in accordance with claim 3 including a parallel bar linkage pivotally connected about vertically spaced pivots to said frame on the other side of said blade from said drive wheel and including a rearwardly located link and a caster wheel mounted from said link for swinging about an axis perpendicular to said pivots and for rotation about an axis parallel to said pivots.

12. A roof remover in accordance with claim 11 and further including spring means connected to said frame and to said link for retaining said caster wheel in position.

13. A roof remover comprising a frame, an engine mounted on said frame, a blade mounted on said frame for horizontal reciprocating movement in response to operation of said engine at speeds in accordance with engine speed and adapted for removing roofing material, a drive wheel mounted on said frame, and power delivery means on said frame for delivering power to said drive wheel from said engine independently of power delivery to said blade by said engine and for selectively driving said drive wheel in forward drive and in reverse drive, said power delivery means including a hydrostatic transmission unit including means for providing neutral, forward drive and rearward drive conditions and for controlling the rate of forward and rearward drive independently of the speed of said engine.

14. A roof remover in accordance with claim 13 wherein said power delivery control means includes a disconnect switch interposed between said drive wheel and said hydrostatic transmission unit.

15. A roof remover in accordance with claim 13 wherein said power delivery means includes a control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in a reverse drive condition, for returning said lever to neutral upon removal of a manually applied force acting in opposition to said lever returning means.

16. A roof remover in accordance with claim 13 wherein said power delivery means includes a control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in said forward drive condition, for releasably retaining said lever in a'selection position.

17. A roof remover in accordance with claim 13 wherein said power delivery means includes a pivotally mounted control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in a reverse drive condition, to prevent pivotal movement of said lever in one plane from rearward drive condition to forward drive condition.

18. A roof remover in accordance with' claim 13 wherein said power delivery means includes a guide member having therein a slot with communicating laterally offset legs, a lever pivotally mounted with respect to said guide member and extending through said slot, means biasing said lever in the direction toward the end of one leg adjacent said other leg, and means biasing said lever along its pivotal axis toward said one leg. I

19. A roof remover in accordance with claim 13 including means for selectively driving said blade by said engine independently of the operation of said drive wheel by said engine.

20. A roof remover in accordance with claim 19 wherein said means for selectively driving said blade by said engine includes an endless belt and a device mounted on said frame and including components movable between a first position effecting braking of said belt and a second position in non-braking relation to said belt, said second position effecting tensioning of said belt to afford effective power delivery thereby.

21. A roof remover in accordance with claim 20 wherein at least some of the said components are biased to said first or belt braking position and including a control handle having an over-center mounting affording movement between a belt tensioning position and a belt braking position, whereby to effectively overcome said biasing when said handle is in said belt tensioning position. 7

22. A roof remover in accordance with claim 13 in cludin g a parallel bar linkage pivotally connected about vertically spaced pivots to said frame on the other side of said blade from said drive wheel and including a rearwardly located link and a caster wheel mounted from said link for swinging about an axis perpendicular to said pivots and for rotation about an axis parallel to said pivots.

23. A roof remover in accordance with claim 22 and further including spring means connected to said frame and to said link for retaining said caster wheel in positron.

24. A roof remover comprising a frame, an engine mounted on said frame, a blade mounted on said frame for horizontal reciprocating movement in response to operation of said engine at speeds in accordance with engine speed, said blade being U-shaped and including a web and an upstanding leg at each end of said web, said web and said legs including forwardly and rearwardly located cutting edges, a drive wheel mounted on said frame, and means on said frame for driving said drive wheel by said engine independently of operation of said blade by said engine.

25. A roof remover in accordance claim 24 wherein said drive wheel driving means includes a hydrostatic transmission unit including means for providing neutral, forward drive and rearward drive conditions and for controlling the rate of forward and rearward drive independently of the speed of said engine.

26. A roof remover in accordance with claim 24 including means for selectively driving said blade by said engine independently of the operation of said drive wheel by said engine.

27. A roof remover in accordance with claim 24 ineluding a parallel bar linkage pivotally connected about vertically spaced pivots to said frame on the other side of said blade from said drive wheel and including a rearwardly located link and a caster wheel mounted from said link for swinging about an axis perpendicular to said pivots and for rotation about an axis parallel to said pivots.

28. A roof remover comprising a frame, an engine mounted on said frame, a throttle control connected to said engine, a blade mounted on said frame for reciprocating movement, a drive wheel mounted on said frame, a parallel bar linkage pivotally connected about spaced pivots to said frame and on the other side of said blade from said drive wheel and including a rearwardly located link, a caster wheel mounted from said link for swinging about an axis perpendicular to said pivots and for rotation about an axis parallel to I said pivots, a hydrostatic transmission unit mounted on said frame and including a pump driven by said engine,

an output shaft connected to said drive wheel and means including a lever movable between neutral, forward drive and reverse drive conditions to control the rate and direction of movement of said drive wheel independently of the speed of said engine, and means for releasably driving said blade by said engine independently of the operation of said drive wheel by said engine and including an endless belt and a device mounted on said frame and including components movable between a firstposition effecting braking of said belt and a second position in non-braking relation to said belt, said second position effecting tensioning of said belt to afford effective power delivery thereby.

29. A roof remover in accordance with claim 28 wherein said power delivery control means includes a clutch interposed between said drive wheel and said hydrostatic transmission unit.

30. A roof remover in accordance with claim- 28 wherein said blade has forwardly and rearwardly located cutting edges.

31. A roof remover comprising a frame, an engine mounted on said frame, a blade mounted on said frame for horizontal reciprocating movement in response to operation of said engine at speeds in accordance with engine speed, said blade having forward and rearward cutting edges, a drive wheel mounted on said frame, and power delivery means on said frame for selectively driving said drive wheel in forward drive and in reverse drive.

32. A roof remover in accordance with claim 31 including means for selectively driving said blade by said engine independently of the operation of said drive wheel by said engine.

33. A roof remover in accordance with claim 32 wherein said means for selectively driving said blade by said engine includes an endless belt and a device mounted on said frame and including components movable between a first position effecting braking of said belt and a second position in non-braking relation to said belt, said second position effecting tensioning of said belt to afford effective power delivery thereby.

34. A roof remover in accordance with claim 33 wherein at least some of said components are biased to said first or belt braking position and including a control handle having an over-center mounting affording movement between a belt tensioning position and a belt braking position, whereby to effectively overcome said static transmission unit including means for providing neutral, forward drive and rearward drive conditions and for controlling the rate of forward and rearward drive independently of the speed of said engine.

36. A roof remover in accordance with claim 35 wherein said power delivery control means includes a clutch interposed between said drive wheel and said hydrostatic transmission unit. 

1. A method of stripping roofing material from a roof comprising the steps of reciprocating a blade having horizontal and vertical cutting edges relative to the roofing material, translating the blade into the roofing material while continuing said reciprocating of the blade so as to cut the roofing material both horizontally and vertically to form a strip of roofing material served from the roof, translating the blade in the opposite direction from the previous translation while maintaining said reciprocating of the blade, and simultaneously turning the blade across the previous path of the blade so as to cut the roofing material with the rear of the blade.
 2. A method of stripping roofing material from a roof comprising the steps of reciprocating a cutting blade having a web with a cutting edge and a supporting leg with a cutting edge relative to the roofing material, simultaneously translating the blade into the roofing material to cut the roofing material by the web and the leg of the blade, translating the blade in the opposite direction from the previous translation while maintaining said reciprocating of the blade, and simultaneously turning the blade across the previous path of the blade so as to cut the roofing material with the rear of the blade.
 3. A roof remover comprising a frame, an engine mounted on said frame, a blade having sharpened forward and rearward edges and being mounted on said frame for horizontal reciprocating movement in response to operation of said engine at speeds in accordance with engine speed, a drive wheel mounted on said frame, and power delivery means on said frame for delivering power to said drive wheel from said engine independently of power delivery to said blade by said engine and for selectively driving said drive wheel in forward drive and in reverse drive.
 4. A roof remover in accordance with claim 3 wherein said power delivery means includes a control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in a reverse drive condition, for returning said lever to neutral upon removal of a manually applied force acting in opposition to said lever returning means.
 5. A roof remover in accordance with claim 3 wherein said power delivery means includes a control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in said forward drive condition, for releasably retaining said lever in a selection position.
 6. A roof remover in accordance with claim 3 wherein said power delivery means includes a pivotally mounted control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in a reverse drive condition, to prevent pivotal movement of said lever in one plane from rearward drive condition to forward drive condition.
 7. A roof remover in accordance with claim 3 wherein said power delivery means includes a guide member having therein a slot with communicating laterally offset legs, a lever pivotally mounted with respect to said guide member and extending through said slot, means biasing said lever in the direction toward the end of one leg adjacent said other leg, and means biasing said lever along its pivotal axis toward said one leg.
 8. A roof remover in accordance with claim 3 including means for selectively driving said blade by said engine independently of the operation of said drive wheel by said engine.
 9. A roof remover in accordance with claim 8 wherein said means for selectively driving said blade by said engine includes an endless belt and a device mounted on said frame and including components movable between a first position effecting braking of said belt and a second position in non-braking relation to said belt, said second position effecting tensioning of said belt to afford effective power delivery thereby.
 10. A roof remover in accordance with claim 9 wherein at least some of the said components are biased to said first or belt braking position and including a control handle having an over-center mounting affording movement between a belt tensioning position and a belt braking position, whereby to effectively overcome said biasing means when said handle is in said belt tensioning position.
 11. A roof remover in accordance with claim 3 including a parallel bar linkage pivotally connected about vertically spaced pivots to said frame on the other side of said blade from said drive wheel and including a rearwardly located link and a caster wheel mounted from said link for swinging about an axis perpendicular to said pivots and for Rotation about an axis parallel to said pivots.
 12. A roof remover in accordance with claim 11 and further including spring means connected to said frame and to said link for retaining said caster wheel in position.
 13. A roof remover comprising a frame, an engine mounted on said frame, a blade mounted on said frame for horizontal reciprocating movement in response to operation of said engine at speeds in accordance with engine speed and adapted for removing roofing material, a drive wheel mounted on said frame, and power delivery means on said frame for delivering power to said drive wheel from said engine independently of power delivery to said blade by said engine and for selectively driving said drive wheel in forward drive and in reverse drive, said power delivery means including a hydrostatic transmission unit including means for providing neutral, forward drive and rearward drive conditions and for controlling the rate of forward and rearward drive independently of the speed of said engine.
 14. A roof remover in accordance with claim 13 wherein said power delivery control means includes a disconnect switch interposed between said drive wheel and said hydrostatic transmission unit.
 15. A roof remover in accordance with claim 13 wherein said power delivery means includes a control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in a reverse drive condition, for returning said lever to neutral upon removal of a manually applied force acting in opposition to said lever returning means.
 16. A roof remover in accordance with claim 13 wherein said power delivery means includes a control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in said forward drive condition, for releasably retaining said lever in a selection position.
 17. A roof remover in accordance with claim 13 wherein said power delivery means includes a pivotally mounted control lever movable between neutral, forward drive and reverse drive conditions, and means operable, when said lever is in a reverse drive condition, to prevent pivotal movement of said lever in one plane from rearward drive condition to forward drive condition.
 18. A roof remover in accordance with claim 13 wherein said power delivery means includes a guide member having therein a slot with communicating laterally offset legs, a lever pivotally mounted with respect to said guide member and extending through said slot, means biasing said lever in the direction toward the end of one leg adjacent said other leg, and means biasing said lever along its pivotal axis toward said one leg.
 19. A roof remover in accordance with claim 13 including means for selectively driving said blade by said engine independently of the operation of said drive wheel by said engine.
 20. A roof remover in accordance with claim 19 wherein said means for selectively driving said blade by said engine includes an endless belt and a device mounted on said frame and including components movable between a first position effecting braking of said belt and a second position in non-braking relation to said belt, said second position effecting tensioning of said belt to afford effective power delivery thereby.
 21. A roof remover in accordance with claim 20 wherein at least some of the said components are biased to said first or belt braking position and including a control handle having an over-center mounting affording movement between a belt tensioning position and a belt braking position, whereby to effectively overcome said biasing means when said handle is in said belt tensioning position.
 22. A roof remover in accordance with claim 13 including a parallel bar linkage pivotally connected about vertically spaced pivots to said frame on the other side of said blade from said drive wheel and including a rearwardly located link and a caster wheel mounted from said link for swinging about an axis perpendicular to said pivots and for rotation about an axis parallel to said pivots.
 23. A roof remover in accordance with claim 22 and further including spring means connected to said frame and to said link for retaining said caster wheel in position.
 24. A roof remover comprising a frame, an engine mounted on said frame, a blade mounted on said frame for horizontal reciprocating movement in response to operation of said engine at speeds in accordance with engine speed, said blade being U-shaped and including a web and an upstanding leg at each end of said web, said web and said legs including forwardly and rearwardly located cutting edges, a drive wheel mounted on said frame, and means on said frame for driving said drive wheel by said engine independently of operation of said blade by said engine.
 25. A roof remover in accordance with claim 24 wherein said drive wheel driving means includes a hydrostatic transmission unit including means for providing neutral, forward drive and rearward drive conditions and for controlling the rate of forward and rearward drive independently of the speed of said engine.
 26. A roof remover in accordance with claim 24 including means for selectively driving said blade by said engine independently of the operation of said drive wheel by said engine.
 27. A roof remover in accordance with claim 24 including a parallel bar linkage pivotally connected about vertically spaced pivots to said frame on the other side of said blade from said drive wheel and including a rearwardly located link and a caster wheel mounted from said link for swinging about an axis perpendicular to said pivots and for rotation about an axis parallel to said pivots.
 28. A roof remover comprising a frame, an engine mounted on said frame, a throttle control connected to said engine, a blade mounted on said frame for reciprocating movement, a drive wheel mounted on said frame, a parallel bar linkage pivotally connected about spaced pivots to said frame and on the other side of said blade from said drive wheel and including a rearwardly located link, a caster wheel mounted from said link for swinging about an axis perpendicular to said pivots and for rotation about an axis parallel to said pivots, a hydrostatic transmission unit mounted on said frame and including a pump driven by said engine, an output shaft connected to said drive wheel and means including a lever movable between neutral, forward drive and reverse drive conditions to control the rate and direction of movement of said drive wheel independently of the speed of said engine, and means for releasably driving said blade by said engine independently of the operation of said drive wheel by said engine and including an endless belt and a device mounted on said frame and including components movable between a first position effecting braking of said belt and a second position in non-braking relation to said belt, said second position effecting tensioning of said belt to afford effective power delivery thereby.
 29. A roof remover in accordance with claim 28 wherein said power delivery control means includes a clutch interposed between said drive wheel and said hydrostatic transmission unit.
 30. A roof remover in accordance with claim 28 wherein said blade has forwardly and rearwardly located cutting edges.
 31. A roof remover comprising a frame, an engine mounted on said frame, a blade mounted on said frame for horizontal reciprocating movement in response to operation of said engine at speeds in accordance with engine speed, said blade having forward and rearward cutting edges, a drive wheel mounted on said frame, and power delivery means on said frame for selectively driving said drive wheel in forward drive and in reverse drive.
 32. A roof remover in accordance with claim 31 including means for selectively driving said blade by said engine independently of the operation of said drive wheel by said engine.
 33. A roof remover in accordance with claim 32 wherein said means for selectively driving said bladE by said engine includes an endless belt and a device mounted on said frame and including components movable between a first position effecting braking of said belt and a second position in non-braking relation to said belt, said second position effecting tensioning of said belt to afford effective power delivery thereby.
 34. A roof remover in accordance with claim 33 wherein at least some of said components are biased to said first or belt braking position and including a control handle having an over-center mounting affording movement between a belt tensioning position and a belt braking position, whereby to effectively overcome said biasing means when said handle is in said belt tensioning position.
 35. A roof remover in accordance with claim 31 wherein said power delivery means comprises a hydrostatic transmission unit including means for providing neutral, forward drive and rearward drive conditions and for controlling the rate of forward and rearward drive independently of the speed of said engine.
 36. A roof remover in accordance with claim 35 wherein said power delivery control means includes a clutch interposed between said drive wheel and said hydrostatic transmission unit. 